The present invention relates to an improved device for manufacturing textile products directly from fibers and/or filaments. The invention also relates to a process for using the device.
The present invention relates substantially to the production of products obtained by the technique known as the xe2x80x9cverticalization techniquexe2x80x9d and which has been refined by the Applicant.
This technique is described in European patent EP A 0,479,880 and allows textile products and more specifically floor and/or wall coverings of carpet type to be produced directly from fibers and, or filaments travelling in the form of a web.
The Applicant has also proposed in document EP A 0,783,608 to adapt this technique to the production of knitted products.
The verticalization technique described consists in subjecting the fibers and/or filaments to a xe2x80x9ctransverse loopingxe2x80x9d accompanied by a xe2x80x9cdrawingxe2x80x9d and in obtaining an accumulation of the fibers and/or filaments in the form of a xe2x80x9cpseudo-yarnxe2x80x9d in which the fibers and/or filaments are parallelized.
In these documents, it is described that the transverse looping accompanied by drawing is carried out for each individual fiber or filament by means of rotary looping elements or discs, which are spaced apart and arranged on a shaft transverse to the direction of advance of the web and between which are arranged looping fingers. In this way, each fiber or filament is, in principle, involved in at least one looping so as to form a twistless pseudo-yarn obtained by the accumulation of the exactly parallelized elementary fibers and/or filaments. This twistless pseudo-yarn consisting of the parallelized fibers and/or filaments may be either manipulated by needles of tufting needle type and may be conveyed towards a support in order to make carpets as described in details in publication EP A 0,479,880, or may be entrained by knitting needles in order to produce knitted products as described in details in publication EP A 0,783,608, or alternatively may be used to produce products of lapsed-bonded type as described in details in publication EP A 0,960,227.
The conditions which had been established at the time of filing of patent application EP A 0,479,880 appeared to be twofold: firstly, most of the components constituting the web, i.e. the individual fibers and/or filaments, needed to have an angle of orientation with respect to the feed direction of the web which was between 5 and 45 degrees and more specifically between 15 and 25 degrees; secondly, the web of fibers and/or filaments at the outset needed to have a low weight per unit area, preferably between 10 and 50 g/m2.
The condition relating to the orientation which the fibers and/or filaments need to have relative to the feed direction is a minimum condition of profitability as regards the lower angle. The reason for this is that, below a particular angle, the fibers and/or filaments run the risk of no longer being correctly parallelized during the production of the pseudo-yarn, thus impairing the efficiency of the product. By contrast, as regards the maximum angle, this is an angle which constitutes a compromise between theory and practice, that is to say that when fibers and/or filaments have an angle greater than this limit of 45 degrees, it is considered that, in theory, the process could still be carried out, but it is observed that the fibers and/or filaments would generate forces which increase exponentially with the angle of orientation of the fibers for the device formed by the interpenetration of the looping discs with the looping fingers, which would thus necessitate an oversizing of the parts, and in particular of the shaft supporting the looping discs.
At the time of production of the prototype using the process described in the patent, the Applicant had therefore proposed to satisfy the first of the conditions by ensuring an orientation of the fibers relative to the feed direction by means of a xe2x80x9ctransverse pre-drawingxe2x80x9d which was substantially carried out by the interpenetration of two sets of discs arranged upstream of the looping discs/looping fingers device.
Nevertheless, at the time of production of a machine with a width of 4 m, for example, such a technical solution proved difficult to implement for the following reasons: the difficulty in controlling the lateral expansion of the web at high speed (formation of folds, etc.) under satisfactory productivity conditions; the difficulty in suitably orienting certain types of fibers, and in particular fibers longer than 250 mm or continuous filaments.
In publication WO 97/05315, the Applicant had proposed a process known as the DUO process in which the processing of the fibers and/or filaments is split by carrying out a pre-looping step which is referred to as the crimping step. The looping step is carried out conventionally using a device consisting of the interpenetration of a first set of looping discs with a first set of looping fingers, while the prior crimping step is also carried out using a device consisting of the interpenetration of a second set of discs known as crimping discs with a second set of fingers known as crimping fingers. The process described in publication WO 97/05315 was characterized in that the crimping device arranged upstream of the looping device relative to the feed direction had a gauge which was a multiple of the gauge of the looping device. This configuration made it possible in a particularly advantageous manner to reduce the forces applied on the fibers during their processing and to produce a product without breaking fibers while at the same time limiting the dimensions of the machine parts.
Although this solution was tested successfully at the industrial scale, it has a certain number of drawbacks. In particular, implementing such a process requires the presence of machines arranged upstream of the present device and consisting of a of long-fiber carding machine 2.5 m wide and its feeder, a conventional lap machine lapping in a width of 4 m and also a longitudinal stretcher. This type of line intended to feed a 4 m device makes it possible to produce/process up to 800 kilos per hour.
The device consisting of the crimping assembly and the looping assembly producing the DUO device made it possible to obtain a stroke speed of 1000 strokes per minute according to the limits of the current technology, thus making it possible to produce/process between 200 and 250 kilos per hour, whereas a conventional nonwoven line remains three to four times more productive than a device of DUO type as described above.
This results in an inadequacy between upstream production (card/lapper/drawer) and downstream device (DUO device) which in practice is reflected by excessive investments costs and mediocre profitability.
In addition, the fact that a large number of upstream devices or machines is proposed proves to be difficult to manage. A critical point consists of the stoppages caused by machine faults, in particular of the downstream devices (DUO device). Specifically, the inertia of the carding machine makes it necessary to recycle the web and then reintroduce it into the DUO machine.
Another drawback arises as regards the covering quality, that is to say the superposition of the webs at the folds. Poor covering will inevitably be reflected by the appearance of a darker or lighter transverse line in the finished products.
Finally, the relative complexity of the DUO devices, which are difficult to adjust, may cause fouling zones for certain fibers.
In particular, the presence of detaching elements or strippers in the pre-looping device requires a precise adjustment of their arrangement, which will vary according to the nature of the fiber used. Moreover, after disassembly following jamming, for example, it is relatively difficult to reposition these detaching or stripping elements.
The present invention aims to solve these various problems while at the same time allowing the use of inexpensive and better suited upstream equipment, and in particular the use of carding machines of cotton carding machine type which are carding machines for short fibers optionally with elimination of the lap machine and its replacement with a transverse drawer.
The present invention aims also to dispense with the presence of detaching elements, and thus to simplify the production of the verticalization devices.
Finally, the present invention aims, by reducing the forces, to reduce the sizes of the various members and in particular of the rotary members in the verticalization devices.
The present invention relates to a device for manufacturing textile products from fibers and/or filaments travelling in the form of a web, consisting substantially of the interpenetration of a set of identical spaced-apart looping discs located on a common transverse shaft with a set of identical looping fingers, characterized in that the looping discs have on their perimeter teeth that are relatively spaced apart.
The expression xe2x80x9crelatively spaced apartxe2x80x9d means that the distance separating two successive teeth on the perimeter of a looping disc is at least three times the width of an individual tooth.
Preferably, the number of teeth on the perimeter of a looping disc is between 8 and 16.
Preferably, the distance between two successive teeth on the perimeter of a looping disc is between 20 and 60 mm.
Preferably, the height of the teeth is between 1 and 5 mm.
Advantageously, the slope of the teeth facing the arrival of the web is between 20 and 40 degrees.
Advantageously, the distance between two successive teeth on the perimeter of a looping disc does not exceed 1.5 times the average length of the fibers and/or filaments of the web.
A transfer member, preferably a knitting element or a needle, is arranged in the extension of each looping finger. These transfer members, and preferably the needles, carry out a rectilinear sinusoidal movement obtained using a rod/cam system.
In addition, the rotational movement of the looping discs located on a common transverse shaft is uniform.
Advantageously, the movement of the transfer elements or needles and the rotational movement of the looping discs is obtained with the aid of a single main control arm supporting cams and having a gear reduction which is defined by the number of teeth.
The present invention also relates to a process for manufacturing textile products from fibers and/or filaments travelling in the form of a web, in which: the fibers and/or filaments are subjected to a transverse looping accompanied by a drawing using an assembly consisting of the interpenetration of a set of identical spaced-apart looping discs located on a common transverse shaft with a set of identical looping fingers, the looping discs having on their perimeter teeth that are relatively spaced apart; the fibers and/or filaments are accumulated in the form of at least one crimped pseudo-yarn of a certain length in which the fibers and/or filaments are parallelized, this accumulation of said fibers and/or filaments being carried out against the slope of a tooth facing the arrival of the web; and, the crimped pseudo-yarn is transferred towards knitting elements or the set of needles simultaneously over the entire length of the pseudo-yarn. Preferably, the web of fibers and/or filaments has on entry a weight of between 10 and 30 g/m2.
Advantageously, the average orientation of the fibers and/or filaments in the web when entering the device is between 10 and 25 degrees relative to the feed direction of the web.
Advantageously, the entry web consists of fibers and/or filaments between 20 and 70 mm in length.
Preferably, a transverse drawing is carried out on the web prior to the first step consisting in subjecting the fibers and/or filaments to a transverse looping accompanied by a drawing.